What would happen if i lengthen my kite lines to twice their usual length?
Is there more wind higher up? Launching would be interesting.
... yeah I tried it once with my Rhino '06 20m and it sucked. Mind you, I could ride upwind (sort of) and with kite at the edge of the window, forward loop it and you wouldn't miss a beat still going upwind. All that room for even a slow turning kite, was easy to do.
Delayed steering and not as good upwind was the glaring results, infact there really was nothing gained in the exercise. I'm sure you could design a kite with 50/60m lines that would work then maybe its an advantage but not with kites designed around 20/25m lines.
Anyway, do it for the fun of it, give it a go.
cheers
Robbie 
Did it with a big kite in low wind one day and was able to go upwind with the double length lines when it was impossible with single length. I call that worth it.
Glad I didn't ditch it though, that may not have turned out well...
50 meter lines do infact work well, if you want to go kiting in light wind. However I have found 35 the best length for light wind kiting (and often even heavy wind racing) as the kite still turns properly whilst giving you lots of power. It helps racing downwind as you can do longer powerstrokes
